Japanese Patent Application Laid-Open No. 2005-318708 discloses a power generation system in which a free-piston engine (a fluid pressure cylinder) and a linear generator cooperate with each other to generate power.
As with a cylinder structure of an automobile engine, the free-piston engine (fluid pressure cylinder) constituting the power generation system is a single-combustion chamber-type cylinder comprising a combustion chamber (a fluid pressure chamber) provided at only one end of a cylinder. The intake process, the compression process, and the exhaust process of the free-piston engine are carried out by moving a piston in only one direction by the fluid pressure generated by burning and explosion of fuel in the single combustion chamber, and moving the piston in the other direction by driving the linear generator as a motor. The output of power generation is taken out from the linear generator in the burning and explosion of the free-piston engine.
The linear power generation system according to Japanese Patent Application Laid-Open No. 2005-318708 has the structure in which the burning and explosion in the free-piston engine (the fluid pressure cylinder) comprising the single-combustion-chamber-type cylinder and the function of the linear generator as a motor cooperate with each other to reciprocate the piston of the free-piston engine in the axis direction, and the coil of the linear generator serves as a component of the motor and the generator. When the linear power generation system and a controller for controlling the linear power generation system are provided, there is a problem that the structure is complicated and the cost is high.
Further, since the piston is moved in one direction by the burning and explosion and moved in the other direction by the motor, there is a problem that the power generation is inefficient.
Furthermore, since the free-piston engine and the linear generator are connected in series, the size and length are increased, and thus an excessive occupied space is required.